According to a review of adverse event reports submitted to the FDA, Pradaxa bleeding problems appear to be five times more likely to result in death than those associated with warfarin, a much older blood thinner.

The Institute for Safe Medication Practices (ISMP) conducted an analysis of complaints sent to the FDA involving various anticoagulant medications in the group’s latest QuarterWatch report (PDF), which covers adverse event reports from the second quarter of 2012. The report looked at reports of bleeding problems submitted by doctors and patients that were associated with use of Pradaxa, warfarin, and Xarelto.

In the second quarter of 2012, Pradaxa generated 956 adverse event complaints, with 178 of those involving the death of the patient. By comparison, warfarin was linked to 214 complaints, with only 14 deaths.

Lack of Antidote May Be a Factor

ISMP said it conducted the comparison to look at the possible effects of Pradaxa not having a reversal agent. With warfarin, sold under the brand name Coumadin, a doctor can give a patient vitamin K to stop the drug’s anticoagulant effects when a bleeding problem happens. There is no such reversal agent for Pradaxa.

The report notes that a New Zealand study found that in addition to the lack of a Pradaxa antidote, prescribing errors, kidney problems and older patient age may also play a factor in Pradaxa deaths. Reporting bias due to Pradaxa media attention could also play a role, according to the ISMP.

Researchers concluded that there is a need for a Pradaxa risk study that looks at death rates and appropriate ways to treat Pradaxa bleeding events.

Boehringer Ingelheim responded to ISMP’s report by noting that its own study found that major bleeding outcomes from Pradaxa appeared to be better than those with warfarin and found that the rate of hospitalization was about the same for the two drugs. The comments noted in the ISMP report do not address the increased death rates. However, the company objected to the use of adverse event reports as a basis of analysis, indicating that there may be important differences in the underlying populations of those who report Pradaxa bleeding problems.

Pradaxa Lawsuits

Pradaxa (dabigitran) is an anticoagulant that was introduced by Boehringer Ingelheim in October 2010 for prevention of strokes in patients with atrial fibrillation.

About 200 Pradaxa bleeding lawsuits have been filed against Boehringer Ingelheim, alleging that the drug maker failed to adequately warn about the risk of serious or fatal health problems and the lack of a reversal agent to stop bleeding problems that may develop.

In the federal court system, the Pradaxa litigation is centralized before U.S. District Judge David R. Herndon as part of an MDL, or multidistrict litigation. A case management plan has been established where a handful of cases are being prepared for early trial dates, which are expected to go to trial in August 2014. Judge Herndon has also ordered the parties to meet every month starting in August 2013, to discuss potential Pradaxa settlement agreements.